On extended energy-loss fine structure data analysis for obtaining reliable structural parameters

We examined extended energy-loss fine structure (EXELFS) data analysis for obtaining reliable values of structural parameters, and its practical guidelines are presented. We found that the ratio method is unstable and gives reliable results only when the calculated radial distribution function shows good peak separation, whereas the curve-fitting is rather robust for the quantitative analysis. We introduced a simple optimization method to avoid the instability associated with the ratio method so that two experiments on the same area at different temperatures should give the same coordination number. The coordination number and Debye-Waller factor derived from the area having different thickness resulted in the same values within the experimental accuracy up to the thickness of 0.4 λ. (λ: plasmon mean free path), while the inter-atomic distance was linearly decreased with sample thickness also up to that thickness. This suggests that EXELFS experiments must be conducted for sample thickness